Test Blasts to Start In 2 Weeks at Site For Subway Tunnel

In about two weeks test ex­plosions will be conducted in the bedrock at East 63d and East 64th Streets between York Ave­nue and the East River.

The dynamite blasts will he, set off by the Transit Authority to determine whether the blast­ing for the projected new sub­way tunnel from East 64th, Street across the river to Queens would interfere with delicate instruments at the Rockefeller Institute on East 67th Street.

Joseph E. O’Grady, chairman of the authority, said yesterday that 11 holes were being drilled on East 63d and 64th Streets for the blasts. Mr. O’Grady spoke at a press conference in the authority's offices at 370 Jay Street, Brooklyn.

He said that the holes, four inches in diameter, would go down 90 feet and that they were expected to be completed in two weeks. He added that it would take a week or more to set off the test explosions.

Seismographic readings to determine the effect that trains using the tunnel would have on the institute's instruments have been taken in recent weeks by the Rev. Joseph Lynch, the Fordham University seismolo­gist, and scientists working with him.

They took the readings at subway locations in tunnels and rock formations that approxi­mate those for the projected tunnel.

Father Lynch has completed his report and has submitted it to the authority and the in­stitute. However, its contents will not be made public until the dynamite tests are com­pleted.

Mr. O’Grady said yesterday that the authority would an­nounce in six weeks whether it would go ahead with plans to build the tunnel from 64th Street or from another location.

The authority has run into opposition ever since it an­nounced plans last year to build the $27,450,000 tunnel to Long Island City.

Opposition has come from Rockefeller scientists, and busi­ness and civic groups have sought to have the tunnel start from 61st Street. However, the authority has insisted that en­gineering reasons made 64th Street a better site.

The authority has contended that because of the depth of the river and the underlying rock at 61st Street it would cost $8.8 million more to build the tunnel there than at 64th Street.